Issue #8188: Comparisons between Decimal objects and other numeric
objects (Fraction, float, complex, int) now all function as expected.
diff --git a/Lib/decimal.py b/Lib/decimal.py
index 29ce398..0e6a966 100644
--- a/Lib/decimal.py
+++ b/Lib/decimal.py
@@ -862,7 +862,7 @@
# that specified by IEEE 754.
def __eq__(self, other, context=None):
- other = _convert_other(other, allow_float = True)
+ self, other = _convert_for_comparison(self, other, equality_op=True)
if other is NotImplemented:
return other
if self._check_nans(other, context):
@@ -870,7 +870,7 @@
return self._cmp(other) == 0
def __ne__(self, other, context=None):
- other = _convert_other(other, allow_float = True)
+ self, other = _convert_for_comparison(self, other, equality_op=True)
if other is NotImplemented:
return other
if self._check_nans(other, context):
@@ -879,7 +879,7 @@
def __lt__(self, other, context=None):
- other = _convert_other(other, allow_float = True)
+ self, other = _convert_for_comparison(self, other)
if other is NotImplemented:
return other
ans = self._compare_check_nans(other, context)
@@ -888,7 +888,7 @@
return self._cmp(other) < 0
def __le__(self, other, context=None):
- other = _convert_other(other, allow_float = True)
+ self, other = _convert_for_comparison(self, other)
if other is NotImplemented:
return other
ans = self._compare_check_nans(other, context)
@@ -897,7 +897,7 @@
return self._cmp(other) <= 0
def __gt__(self, other, context=None):
- other = _convert_other(other, allow_float = True)
+ self, other = _convert_for_comparison(self, other)
if other is NotImplemented:
return other
ans = self._compare_check_nans(other, context)
@@ -906,7 +906,7 @@
return self._cmp(other) > 0
def __ge__(self, other, context=None):
- other = _convert_other(other, allow_float = True)
+ self, other = _convert_for_comparison(self, other)
if other is NotImplemented:
return other
ans = self._compare_check_nans(other, context)
@@ -5860,6 +5860,37 @@
raise TypeError("Unable to convert %s to Decimal" % other)
return NotImplemented
+def _convert_for_comparison(self, other, equality_op=False):
+ """Given a Decimal instance self and a Python object other, return
+ an pair (s, o) of Decimal instances such that "s op o" is
+ equivalent to "self op other" for any of the 6 comparison
+ operators "op".
+
+ """
+ if isinstance(other, Decimal):
+ return self, other
+
+ # Comparison with a Rational instance (also includes integers):
+ # self op n/d <=> self*d op n (for n and d integers, d positive).
+ # A NaN or infinity can be left unchanged without affecting the
+ # comparison result.
+ if isinstance(other, _numbers.Rational):
+ if not self._is_special:
+ self = _dec_from_triple(self._sign,
+ str(int(self._int) * other.denominator),
+ self._exp)
+ return self, Decimal(other.numerator)
+
+ # Comparisons with float and complex types. == and != comparisons
+ # with complex numbers should succeed, returning either True or False
+ # as appropriate. Other comparisons return NotImplemented.
+ if equality_op and isinstance(other, _numbers.Complex) and other.imag == 0:
+ other = other.real
+ if isinstance(other, float):
+ return self, Decimal.from_float(other)
+ return NotImplemented, NotImplemented
+
+
##### Setup Specific Contexts ############################################
# The default context prototype used by Context()